Safety device for drilling rigs



J. H. WILSON Aug. 14, 1951 3 Sheets-Sheet 1 Filed June 25, 1948INVENTOR. John Hart Wits on BY a I i His gent.

Aug. 14, 1951 J. H. WILSON 2,564,457

SAFETY DEVICE FOR DRILLING RIGS Filed June 25, 1948 Sheets-Sheet 2 IN VEN TOR.

J 01m Hart l l ilson Aug. 14, 1951 J. H. WILSON 2,564,457

SAFETY DEVICE FOR DRILLING RIGS Filed June 25, 1948 S-Sheets-Sheet 5 INVEN TOR.

J abnHartWil son .HGENT.

Patented Aug. 14, 1951 U N I T ED S TATES PAT OFF I C E SAFETY DEVICEFOR DRILLING ZRIGS John Hart Wilson, Wichita Falls, rrex.

Application June 25, 1948, Serial No. 35,239

2 Claims. '1

This invention relates to improvements in safety devices for draw worksand. particularly to draw works adapted for use on well drilling rigs ofthe rotary type.

Well drilling apparatus of the rotary type ordinarily includes a rotarytable for rotating the drill-stem in the well. The drill stem issuspended by a traveling block supported by a numbercof leads of a cablewhich cable passes over the crown block at the top of the derrick, withone line passingdownward to the drum vof ithedraw works. Due to theheight of the derrick on which the traveling block is used forwithdrawing the drill stem and pipe from a well, it is necessary toraise the traveling block at high speed, so as to make rapid progress inthe drilling operation. However, several dangers are ever present whilethe traveling block is being raised at high speed, either with orwithout pipe being connected thereto. Workmen necessarily have 'to be inthe derrick while the traveling block is being raised, and if duringthis process, the traveling block hits the sheaves of the crown "block,this frequently results in the breaking .of the cable or in pulling thederrick in, with possible injury or loss of life to the workmen asresult thereof, as well as much damage to the derrick and to thedrilling rig, and if pipe is dropped into the well, the .loss of thewell may .result.

The stopping of the traveling block short of the crown block, has,heretofore, been theresponsibility of the operator or driller of .therotary rig. Sometimes the distance the traveling block travels beforecontacting the crown block is very short and necessitates the use ofvery careful judgment of distance with the traveling block passing up atvery high speed, and the driller could not .always exercise sufficientlyprecise judgment.

Such safety devices as have been proposed heretofore have not beenadequate due to the high speed at which the traveling block travelsupward, and due to the lack of flexibility and yieldability which isnecessary for the successful operation of a device for stopping thetravel of a traveling block within a given distance.

The primary object of this invention is .to improve the construction ofthe drilling apparatus by providing a safety device with a yieldableline which will move in response to the movement of the traveling blockand which will yield readily to action thereon by the traveling blockand line without causing damage to the rig or other equipment, if thestopping of the draw works is not instantaneous.

clutch thereof, which parts are responsive to a resilient safety devicemounted on the derrick to cause'the traveling block to stop withinapredetermined distance of travel.

These objects maybe accomplished, according to the embodiment of theinvention as illustrated in the accompanying drawings, by the provisionof a cable passing transversely across the derrick above the travelingblock and between the block lines that support the traveling block sothat the transverse line will be engaged by the traveling block as itmoves upward in the derrick above a predetermined point. The engagementof the transverse cable by the traveling block will actuate the controlmechanism of the .brake and .clutchof the draw works to-oause the latterto respond thereto.

The transverse cable that passes above the traveling block .is connectedwith pneumatic controls that actuate the brake and disengage the clutch,upon the engagement of the transverse line by the traveling block. Thusthe draw works will be brought to a stop within the predetermined limitsof travel of the traveling block so as to cause no undue shock on the.rig. Any desired range of stopmay be provided for, from instantaneousto the maximum travel accorded by the weight attached to the transversecable.

This embodiment of theinvention is illustrated in the accompanyingdrawings, in which:

Fig. 1 is a perspective view of a derrick, show 'ing the inventionapplied thereto;

Fig. '2 is a side elevational view of a traveling block and the linesassociated therewith, with the safety cable shown in section;

Fig. 3 is affragmentary View of a portion of a derrick, partly insection, showing the weight and weight guide member attached thereto;

Fig. 4 is a diagrammatic side elevation showing the controls actuated bythe safety cable;

Fig. 5 is a side elevation of a master clutch.

The invention is shown as applied to a rotary drilling rig whichcomprises a derrick I and a conventional draw works generally designatedat D. The derrick I has mounted at the top thereof, in the usual manner,a conventional crown block 2 for supporting line 3 which extendsdownward from the crown block 2 in multiple loops, in which thetraveling block 4 is suspended for supporting the drill stem or pipeduring the raising and lowering operation thereof while drilling a well.Thedrill stem is rotated by the conventional rotary table (not shown),which rotary table is usually driven by the draw works D mounted on thefloor at the base of the derrick I. The draw works D includes a drum 6upon which a cable is wound to raise and lower the traveling block 4, asshown in Figs. 1 and 4. The line 3 is attached to the drum 6 which isgenerally known as the fast line, and which is adapted to raise andlower the traveling block in response to the rotation of the drum 6.

Extending transversely through the derrick I is a safety cable orflexible device 8 passing over pulleys 9 on opposite sides of thederrick and supporting a weight II] on one end thereof. The weight In isguided on a rod IOa spaced from but secured to frame lob, which frame isclamped to the derrick by means of clamps Illc. By having the weight It]so positioned and guided by the rod IIla, the transverse cable 8 isrelieved of the weight I until such time as the safety device is broughtinto action. The frame IIlb restrains the weight I!) against falling, inevent the cable 8 becomes broken. This safety cable 8 extends throughthe loops in the line 3 and is disposed directly over a V-yoke IIsecured to the top of the traveling block 4, as shown in Fig. 2. Thusthe line 8 is in a position to be engaged by the yoke I I, as thetraveling block moves upward in the derrick I and to be moved therebyfrom the full-line position in Fig. 1 to the dotted-line positiontherein, the yoke I! insuring engagement of the safety line B by thetraveling block and causing it to move in response thereto. Normally themovement of the cable 8 would be much less than that shown in thedrawings, which is somewhat exaggerated for the purpose of illustration.

The cable 8 may be formed of any suitable material, although a wire lineis the most satisfactory for the purpose. However, it may be ofnon-metallic material, if desired, and will function satisfactorily tocontrol the operation of the draw works as hereinafter described.

The line 8 extends along the derrick substantially to the bottomthereof, where its lower end is attached to an arm I2 mounted on a leverI3 and cooperating with the latter to form substantially a bell crank.The lower end of the lever I3 engages a notch I4 formed in one side of alug I5 secured to an operating lever I5.

A connecting rod I1 extends downwardly from the lever I6 in the formillustrated in Fig. 4, and is connected at its lower end to an arm ofthe bell crank lever generally indicated at I8, which bell crank leveris pivotally mounted at I9. The other arm of the bell crank lever I8 hasa spring 2!! connected to its extreme lower end, and normally tending toswing the bell crank lever I8 in a clockwise direction, as viewed inFig. 4. The opposite end of the spring is anchored to a part of theframe 2| of the draw works.

Also connected with the depending arm of the bell crank lever I8 is aconnecting rod 22 which extends therefrom to one end of a lever 23pivotally mounted on a shaft 24, this lever being fixed to the shaft andmovable about the axis thereof.

The draw works, generally designated in the drawing as D, include apneumatic power brake, generally indicated at 25, which brake is appliedto retard the movement of or to stop the drum. The entire draw works iscontrolled by a master clutch which is regulated by the pneumaticcontrol device generally designated at 26. These eled ments are adaptedto be controlled by the engagement of the safety line 8.

The brake 25 is illustrated as controlled by a Segment 21 of a gearwhich is connected with a pneumatic power device 28, by a chain 21a. Air

is supplied to the pneumatic power device 28 through a line 29 extendingto a valve 30, thence through a line 3i which has a valve 32 therein.The opposite side of the valve 32 is connected through a line 33 with amain air source of supply under pressure, as indicated at 34. The valve32 is adapted to be manually controlled by the control device generallyindicated at 35.

Also connected with the source of air supply 34, is a branch line 36which contains a control valve 3'! therein and which branch line 36leads to the line 29 and may connect therethrough to the pneumatic powerdevice 28. The valve 31 is adapted to be closed alternately with thevalve 30, for which purpose the lever 23 engages the valve stem of thevalve 31 at one side of its pivotal axis, while it engages the valvestem of the valve so at the opposite side of the axis thereof, so thatthe lever 23 will cause an opening of one valve simultaneously with theclosing of the other.

Also mounted on the shaft 24 is a control arm 38 connected with acontrol valve 39 which has an air line 48 connected with one sidethereof and leading from the main source of air supply, as indicated at35. The valve 39 is connected also through lines AI with the aircylinder that regulates the master clutch, which is indicated at 26 inFig. 5. The valve 39 is adapted to supply air to the master cylinder 26for regulating the position of the master clutch.

In the operation of the control system, it will be evident that theupward movement of the traveling block 4 and loops 3, which support thetraveling block, will cause the yoke II to engage the safety cable 8 andmove it upward from its normally stretched position in bridging relationbetween the pulleys 9, and tend to deflect this safety cable 8 out ofits normal position. The safety cable 8 has a weight Iii positioned onthe opposite end to that connected to the draw works control lever I2.This weight is adapted to be lifted when the traveling block 4 engagestransverse safety cable 8, which permits the traveling block to moveupward several feet, while allowing the brakes to be applied graduallyso as to prevent undue shock, which would be the result if the travelingblock were stopped instantaneously upon contacting the cable 8. Thispulling action applied to the cable 8 will lift the outer end of the armI2, shown in Fig. 4, and cause an upward swinging movement of the leverI3, which forms a safety catch, disengaging the latter from the notchI4. When thus released, the lever I6 may move upward in response to thetension of the spring 20 acting on the depending arm I8 that isconnected therewith through the bell crank I8 and the connecting rodI'I. Normally, these parts are held in the positions shown in Fig. 4when the latch I3 engages the lug I5 on the lever I6.

This releasing movement of the lever I6, as described, will move theconnecting rod 22 toward the left in Fig. 4, which, thereby, will swingthe lever 23 in a clockwise direction. The effect of this will be toclose the control valve 30 and to open the valve 3?. This will admit airfrom the supply line 34 through the branch line 36 to the power device28 in a direction tending to actuate the latter to apply the brake 25,thus causing the stopping action of the drum 6.

Simultaneously with the application of the brake to the drum 6, therotation of the shaft 24 will swing the arm 38 to move the valve 39 foropening the latter to permit the air to the power device 26 in adirection to release the clutch of the draw works, thereby stopping theapplication of power thereto and allowing full effect of the brake 25 tobe applied to stop the motion of the draw works and of the drum.

These parts will respond readily and quickly to the movement of thesafety cable 8, because of the use of air power devices that arecontrolled thereby. Thus instant response to the actuation of the safetydevice is to be had in controlling the action of the draw works.Therefore, it will be controlled eflectively without danger of injury ordamage to the equipment or to the workmen.

While the invention has been illustrated and described in oneembodiment, it is recognized that variations and changes may be madetherein without departing from the invention except as specified in theclaims.

I claim: I

1. In a well drilling apparatus, a derrick, a draw works having a hoistfor raising and lowering a traveling block, a clutch and a brake forcontrolling the operation of said hoist, a valve for controlling saidclutch and brake, and a lever pivotally secured near the lower end ofthe derrick for actuating said valve, sheaves at the upper end of saidderrick, a traveling block suspended within said derrick, a linesuitably connecting said hoist, said sheaves, and said block for raisingand lowering the block, a transverse cable positioned across saidderrick at a point spaced downwardly from the top thereof and in thepath of movement of said block, a guide member positioned on the upperend of said travcling block to guide the transverse cable thereinto uponupward movement of said traveling block beyond a predetermined safetypoint, one end of said cable being attached to a vertically movableweight, a frame receiving said weight and. confining it to its verticalpath of movement, means for removably and selectively securing saidweight-carrying frame to said derrick, the other end of said cableextending down a side of the derrick, and means operatively connectingsaid other end of the cable with said lever,

.6 whereby the movement of said traveling block may be arrested withinthe length of the yieldability of said transverse cable.

2. In a well drilling apparatus a derrick having girts, a travelingblock, a draw works having a hoist for raising and lowering thetraveling block, which hoist includes winding means, power means, aclutch for connecting and disconnecting said power means and saidwinding means, a brake for said winding means, fluid pressure means foroperating said clutch and said brake, valves controlling the applicationof said fluid pressure means to said clutch and brake, and a pivotallymounted lever operatively connected with said valves to apply the brakeand release the clutch when moved in a given direction, sheaves at theupper end of said derrick, said traveling block being suspended withinsaid derrick, a line suitably connecting said winding means, saidsheaves, and said block for raising and lowering the block, a transversecable positioned across said derrick and spaced downwardly from the topthereof and in the path of movement of said block, a guide memberpositioned on the upper end of said traveling block to guide saidtransverse cable thereinto upon upward movement of said traveling blockbeyond a predetermined safety point, one end of said cable beingattached to a movable weight positioned on a frame that may beselectively secured to a pair of derrick girts within the length of saidderrick, means for removably securing said weight-carrying frame to saidgirts, the other end of said transverse cable extending down a side ofsaid derrick, and means for operatively connecting said other end of thecable with said lever to swing the latter in said given direction so asto arrest the movement of said traveling block within the length of theyieldability of said transverse cable.

JOHN HART WILSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 985,698 Pearson Feb. 28, 19111,425,569 Arnold Aug. 15, 1922 2,241,274 Severson May 6, 1941 2,428,578Nelles Oct. 7, 1947

